S. A. Smith

Triangulating a Cognitive Control Network Using Diffusion-Weighted Magnetic Resonance Imaging (MRI) and Functional MRI

The ability to stop motor responses depends critically on the right inferior frontal cortex (IFC) and also engages a midbrain region consistent with the subthalamic nucleus (STN). Here we used diffusion-weighted imaging (DWI) tractography to show that the IFC and the STN region are connected via a white matter tract, which could underlie a “hyperdirect” pathway for basal ganglia control. Using a novel method of “triangulation” analysis of tractography data, we also found that both the IFC and the STN region are connected with the presupplementary motor area (preSMA). We hypothesized that the preSMA could play a conflict detection/resolution role within a network between the preSMA, the IFC, and the STN region. A second experiment tested this idea with functional magnetic resonance imaging (fMRI) using a conditional stop-signal paradigm, enabling examination of behavioral and neural signatures of conflict-induced slowing. The preSMA, IFC, and STN region were significantly activated the greater the conflict-induced slowing. Activation corresponded strongly with spatial foci predicted by the DWI tract analysis, as well as with foci activated by complete response inhibition. The results illustrate how tractography can reveal connections that are verifiable with fMRI. The results also demonstrate a three-way functional–anatomical network in the right hemisphere that could either brake or completely stop responses.

Quantitative pathological evidence for axonal loss in normal appearing white matter in multiple sclerosis.

We assessed axonal loss in the normal appearing white matter of the corpus callosum in postmortem brains of patients with multiple sclerosis, using quantitative measures of both axonal density and white matter atrophy. The calculated total number of axons was reduced significantly (mean ± SD, 5.4 × 107 ± 3.1 × 107) compared with normal controls (11.6 × 107 ± 2.2 × 107, p = 0.001) with a reduction both in axonal density (median, 34%; range, 16–56%; p = 0.004) and area (mean ± SD: multiple sclerosis, 584 ± 170 mm2; controls, 871 ± 163 mm2; p = 0.004). These results confirm substantial axonal loss in the normal appearing white matter and demonstrate that measures of both axonal density and white matter volume are necessary to appreciate the full extent of axonal loss. Ann Neurol 2000;47:391–395

Large-Scale Automated Histology in the Pursuit of Connectomes

How does the brain compute? Answering this question necessitates neuronal connectomes, annotated graphs of all synaptic connections within defined brain areas. Further, understanding the energetics of the brains computations requires vascular graphs. The assembly of a connectome requires sensitive hardware tools to measure neuronal and neurovascular features in all three dimensions, as well as software and machine learning for data analysis and visualization. We present the state of the art on the reconstruction of circuits and vasculature that link brain anatomy and function. Analysis at the scale of tens of nanometers yields connections between identified neurons, while analysis at the micrometer scale yields probabilistic rules of connection between neurons and exact vascular connectivity.

Pupil findings in a consecutive series of 150 patients with generalised autonomic neuropathy

Aim: To detect and characterise the pattern and extent of pupil abnormalities in patients with generalised autonomic failure. Methods: A consecutive series of 150 patients referred for investigation of symptomatic generalised autonomic failure underwent pupil investigations. Infra-red video pupillography was used to measure resting pupil diameters in light and dark, the light reflex response, the miosis associated with an accommodative effort, and responses to topical administration of various pharmacological agents. The results were compared with data recorded under identical conditions from a cohort of 315 age-matched and sex-matched healthy controls. Results: Overall, two thirds of patients had abnormal pupils (66%) with sympathetic deficit occurring twice as often as parasympathetic deficit. However, the prevalence and type of pupil abnormality showed wide variation according to aetiology—for example, almost all patients with amyloidosis had abnormal pupils, two thirds with pure autonomic failure but less than a quarter with multiple system atrophy. In most patients (85%), pupil abnormalities were bilateral and symmetrical, none had a Horner’s syndrome in one eye and a tonic pupil in the other. No significant correlation between the type of pupil abnormality and the predominant type of systemic autonomic deficit was seen in most conditions. Conclusions: The pupils are often affected in autonomic neuropathy, although this is not always apparent either to the patient or to their doctors. Considerable care is needed not only to detect these abnormalities but also to interpret correctly the results of pupil tests in this group of patients.

Writing the History of the Russian Revolution after the Fall of Communism

A CHINESE PROVERB speaks of hurling a brick in order to attract jade. The present article is written in that spirit: it presents its arguments boldly in the hope that it will provoke lively and thoughtful reaction. It is an attempt to speculate on the implications of the fall of communism in the former Soviet Union for the writing of the history of the Russian Revolution over the next 20 years. This is self-evidently a foolhardy undertaking, since it is clearly too early to pronounce on the historical significance of the entire Soviet era. Nevertheless the article is written in the conviction that since 1991 the history of the Russian Revolution has become history in a new sense. First, historians have suddenly gained a sharper perspective on the system that was born in October 1917: it can now be seen to have a beginning, a middle and an (uncertain!) end, and it is appropriate to speculate on what this increased hindsight signifies. Second, up to 1989 the continuance of the Soviet regime and the wider system of superpower rivalry meant that study of the Russian Revolution could never be insulated from the short-term pressures of contemporary politics. That is no longer so. It does not mean that the history of the Russian Revolution has ceased to be the object of political controversy and passion, or that the Russian Revolution is over, as Franqois Furet famously pronounced of the French Revolution, but it does allow historians greater scope to determine agendas outside the problematics of sovietology. The article seeks to suggest what such an agenda might look like by linking the fall of communism to the emergence of that condition of postmodernity which has been a notable feature of advanced capitalist societies during the past 20 years. It is my contention that as historians we cannot escape this condition, and that we should seek to utilise what is best in postmodernism in the quest to extend our knowledge of the Soviet past.2

Introduction to the NeuroImage special issue "Mapping the Connectome".

“Connectomics” is the study of connectivity in the brain; the term has come to include the mapping of both structural and functional connectivity, ranging in scale from the microscopic (neuronal-level) to the macroscopic (millimetre). The term “connectome” was only recently coined (Sporns, Hagmann), although “connectome is a term with a short history but a long past” (Catani). This special issue on “Mapping the Connectome” is a review of the major issues and current projects relating to connectomics; it aims to be comprehensive, albeit with a strong bias towards themacroscopic, in vivo, human connectome, as most appropriate for the readership of NeuroImage. This special issue is timely, as the field of connectomics is experiencing rapid growth, but is also reaching some watersheds of maturity, as indicated for example by the milestone Human Connectome Project. In vivo macroscopic connectomics has to date primarily used the imaging modalities of diffusion MRI (dMRI, giving us the “structural” connectome, concentrating on the white matter) and resting-state functional MRI (rfMRI, giving us the “functional” connectome, concentrating on the grey matter). While each has obvious limitations (e.g., one might stereotype dMRI as being prone to suffering from false negatives, and rfMRI as suffering from false positives), their complementarity is so strong that together their combination is a powerful tool. (It is surprising therefore that there has been so little work on joint analysis methods for the two modalities!) Additionally, there are many other sources of connectome-related data, including EEG, MEG, task-fMRI, and more invasive in vivo electrophysiological modalities, as well as the very important connectomic work being carried out at the microscopic level. The special issue is organized into three groups of papers. In the first group, we have a fantastic array of background and overview papers, covering history and anatomy (Catani, Passingham, Caspers), microscopic-level connectomics (Costa, Kennedy, Stephan) and general connectomic history (Sporns). The second group of papers covers major ongoing connectomemapping projects, starting with a canonical set of papers describing the two NIH-funded Human Connectome Projects. The “WU-Minn” HCP is generating a mapping of the (macroscopic-level functional and structural) human connectome in over 1000 subjects, that will be the most comprehensive dataset of this type generated to date

Reliable TLDA-microvolume UV spectroscopy with applications in chemistry and biosciences for microlitre analysis and rapid pipette calibration*

A TLDA-microvolume (transmitted light drop analyser) accessory for use with a standard UV–visible fibre spectrophotometer is described. The physics of the elegantly simple optical design is described along with the experimental testing of this accessory. The modelling of the arrangement is fully explored to investigate the performance of the drop spectrophotometer. The design optimizes the focusing to deliver the highest quality spectra, rapid and simple sample handling and, importantly, no detectable carryover on the single quartz drophead. Results of spectral measurements in a laboratory providing NIST standards show the closest correlation between modelled pathlength and experimental measurement for different drop volumes in the range 0.7–3 µl. This instrument accessory delivers remarkably accurate and reproducible results that are good enough to allow the accessory to be used for rapid pipette calibration to avoid the laborious weighing methods currently employed. Measurements on DNA standards and proteins are given to illustrate the main application area of biochemistry for this accessory. The accessory has a measurement range of at least 0–60 A units without sample dilution and, since there exists an accurate volume–pathlength relationship, the drop volume used in any specific measurement or assay should be optimized to minimize the photometric error. Studies demonstrate that the cleaning of the drophead with lab wipes results in no measurable carryover. This important practical result is confirmed from direct reading of the accessory and an analytical balance which was used to perform carryover studies.

Fear and Rumour in the People's Republic of China in the 1950s

ABSTRACT The article explores the nature of popular fears during the early years of the Peoples Republic of China by examining two types of rumour: those of a ‘secular’ type that told of Chinas defeat in the Korean War, a third world war or an imminent nuclear attack; and those of a ‘supernatural’ type that told of demons out to snatch vital organs or the end of the world. These rumours testified both to the resilience of ancient cosmological beliefs and values and to their capacity to fuse with elements of ‘modern’ politics. The article asks what they tell us about the relationship of the party-state to the populace.

Russian Workers and the Politics of Social Identity

L ewis Siegelbaum and Ronald Suny recently charted the shift in labor history from a materialist approach, which views social class as a position within the relations of production, that has determinative consequences for consciousness, to a discursive one, which treats class as a set of ways of constructing reality by and for interested parties.1 The discursive approach to social class looks not so much to the structured reordering of social relationships engendered by industrial capitalism and urbanization, as to the dissemination of discourses of class, understood as symbolically articulated social practices, which reorder the experience of social actors and mobilize support behind particular projects. This approach seems potentially well suited to Russian history, since class was already writ large on the political and social landscape of late Imperial Russia at a time when the transition to industrial capitalism and urbanization was only just underway. In Soviet Russia, too, class was integral to official ideology, yet social disintegration and the abolition of private property in the means of production had radically undermined classes as objective socioeconomic relationships. A discursive approach draws attention to the importance of political mechanisms in promoting class identities. Down to 1917 the Tsarist government constructed social reality according to soslovie, that is, in terms of the rights and obligations of particular social groups to the state. The language of social class, by contrast, was a nonofficial idiom, and the category of working class, which became so influential after 1905, derived much of its force from the fact that it expressed opposition to the autocracy and its modernizing project. In Soviet Russia, too, as Sheila Fitzpatrick has pointed out, class was constructed largely through political discourse. The Soviet regime undertook a reinvention of class that involved the ascription of class identities to citizens so that the new regime (a self-defined dictatorship of the proletariat) could know its allies from its enemies.2

‘MORAL ECONOMY’ AND PEASANT REVOLUTION IN RUSSIA: 1861–1918

The ‘moral economy’ thesis was first propounded by E. P. Thompson and then developed by James C. Scott, and centres on the idea that in pre-capitalist societies social relations are grounded in a publicly recognised right to subsistence that entails reciprocal rights and obligations between elites and the lower classes. The present article aims to assess the value of the moral economy model in understanding the rural world of lateimperial Russia, especially in the light of recent work on the agrarian economy and the peasant movement of 1917–18. It is primarily concerned with Scott’s work since, unlike Thompson, he concentrated on peasants: in particular, on rural societies in Burma and Vietnam during the depression of the 1930s. In order to avoid falling below the subsistence threshold, he argued, peasants employ a ‘safety-first’ principle, seeking to minimise risks to their subsistence rather than to maximise opportunities to make profit. It was Scott’s contention that villages are moral economies precisely because the overriding objective is not individual maximisation of wealth but the protection of the community as a whole against a subsistence crisis. Peasants judge matters such as rents or taxes or the behaviour of landlords or tax collectors against a standard of justice that is bound up with the reciprocal rights and obligations associated with the subsistence ethic. Scott maintained that Southeast Asian villages created institutions, such as communal land and resources, work sharing or forced generosity, in order to ensure a minimum standard of welfare for every village member. These institutions extended to forms of clientelism in which patrons, in return for the services, deference and loyalty of their clients, ensured that the latter were in position to survive a crisis by offering them a temporary reduction of rent, short-term credit or access to supplementary resources of other kinds. Scott’s model has proved hugely influential in all areas of peasant studies. Yet, from the first, its validity was challenged, even as applied to Vietnam. In a study of anti-colonial movements in Vietnam, Samuel Popkin argued that Scott greatly overestimated the solidarity of the peasantry and insisted that the traditional village was incapable of creating effective subsistence assurance and welfare schemes because of problems of free riders, theft of collective resources and mutual mistrust. From a rational (or public) choice standpoint, Popkin contended that peasants are maximisers of personal or family welfare who invest in children, land, livestock and goods, and prepare for contingencies rather than rely upon a community mechanism that may not work. They act out of self-interest and are unconstrained by moral values or collective norms. The validity of the moral economy approach to Russian peasant society has never been subject to debate in the historiography in the same way that it has in other national